YTTRIA TETRAGONAL ZIRCONIA POLYCRYSTALLINE ELECTROLYTES FOR SOLID-STATE ELECTROCHEMICAL-CELLS

Both the grain-boundary and the lattice resistivity in Y-TZP materials is affected by several ceramic processing variables. These include, sintering temperature, sintering time, cooling rate from high temperatures (>1000°C), post-sinter heat treatments, the level and types of impurities and the spatial distribution of Y2O3 in the starting powders. Because of the inherent large grain-boundary surface area the grain-boundary resistivity in these ceramics is extremely sensitive to the presence and location of glassy impurities. Impedance spectroscopy has been used along with four-probe dc conductivity measurements, scanning and transmission electron microscopy, x-ray photoelectron spectroscopy and x-ray diffraction to understand the grain-boundary and lattice resistivity behaviour in Y-TZP ceramics as a function of various ceramic processing variables. © 1990 Springer-Verlag.